The present invention generally relates to a valve for a refrigerating system of the heat pump type, and more particularly to a novel five-way valve capable of performing simultaneous heating/cooling operations for heat pump type refrigerating systems.
A refrigerating system employing a reversible refrigerating cycle (i.e., a heat pump cycle) normally includes indoor and outdoor heat exchangers connected to a compressor and an expansion valve via a valve for switching heating/cooling operations such as, for instance, a four-way valve. In such a refrigerant flow reversing system, to heat indoor ambient atmosphere during cold weather, the indoor heat exchanger acts as a condenser while the outdoor heat exchanger acts as an evaporator. A typical one of such conventional refrigerating systems is disclosed, for example, in U.S. Pat. No. 2,974,682 to TRASK (1961) and U.S. Pat. No. 2,976,701 to GREENAWALT (1961).
However, the conventional reversible refrigerating system has the following drawbacks in regard to its defrosting operation during cold weather while the indoor heat exchanger is operated as a heater. In particular, every time a defrosting operation is to be performed, the heating/cooling switching valve must be operated to control the system in such a manner that the indoor heat exchanger must stop its heating operation and start its cooling operation. Such cooling operation continues until the defrosting operation is completed. After completion of the defrosting operation, the switching valve is changed over again in order to cause the indoor heat exchanger to perform the normal heating operation. Since the indoor heat exchanger is controlled so as to temporarily operate as a cooling machine for each defrosting operation in this manner, there is a drawback that the efficiency of the refrigerating system during the cold weather is deteriorated. Another problem is that, during the heating operation, a user may feel uncomfortable, though temporarily, due to a cool air flow from the indoor heat exchanger.
It is therefore a primary object of the present invention to provide a novel five-way valve for switching cooling/heating operations which can defrost an outdoor heat exchanger of a reversible refrigerating system without interrupting a heating operation of the indoor heat exchanger.
It is another object of the present invention to provide a five-way valve for switching cooling/heating operations which can be employed in a refrigerant flow reversing system and can assure a reliable switching operation with a simplified structure.